Composition for and method of devitalizing microorganisms



Patented Sept. 29, 1942 COMPOSITION FOR, AND METHOD OF DE- VITALIZINGLHCROORGANISMS Randolph Norris Shreve, West Lafayette, Ind., and MillerWoodson Swaney, Elizabeth, N. J., assignors to Mallinckrodt ChemicalWorks, St. Louis, Mo., a corporation of Missouri No Drawing. Originalapplication May 19, 1938, Serial No. 208,860, now Patent No. 2,216,140,dated October 1, 1940. Divided and this application March 30, 1940,Serial No. 326,968

2 Claims. I (Cl. 167-33) This invention relates to compositions for andmethods of devitalizing microorganisms, and with regard to certain morespecific features, to such compositions including pyridylmercuriccompounds as active constituents thereof.

This application is a division of our copending application Serial No.208,860 filed May 19, 1938, now Patent 2,216,140, which in turn is aconric acetate are reacted together, giving pyridylmercuric acetateaccording to the equation.

From the pyridylmercuric acetate thus formed,

tinuation-in-part of our app ication Serial No.

35,626, filed August 10, 1935, and was copending therewith.

Among the several objects of the invention may be noted the provision ofcompositions of the class described which are of enhanced devitalizingpowers, without exhibiting undesirable toxic characteristics, and whichhave enhanced solub lity over prior analogous compositions; theprovision of methods of devitalizing microorganisms employing newcompositions of matter for this purpose; and the provision, as newcompositions of matter, of a new pyridylmercuric compound valuable as amicroorganisni-devitalizing agent. Other objects will be in part obviousand in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations ofelements, steps and sequence of steps, and features of composition andprocedure, which will be exemplified in the products and methodshereinafter described, and the scope of the application of which will beindicated in the following claims.

Many metallo-organic compounds, such as organic compounds of mercury,have heretofore been found to be valuable devitalizing agents formicroorganisms. A particular class of mercury compounds that have beenfound satisfactory are the phenylmercuric salts, but these arefrequently but slightly soluble in water, this feature obviouslydecreasing their utility. The p esent i vent have discovered thatpyridylmercuric compounds, and, more specifically, the saltpyridylmercuric chloride, likewise possess valuablemicroorganismdevitalizing properties. Bacteriostatic tests in someinstances, as for example against B. coli, show that the pyridylmercuriccompounds are more powerful than the corresponding phenylmercuriccompounds. The pyridylmercuric compounds are generally more soluble inwater, whereby they may be prep in more @011- centrated aqueoussolutions. For this reason alone, they comprise a more advantageousdevitalizing agent than the analogous phenylmercuric salts.

A general method for preparing pyridylmercuric chloride is as follows:Pyridine and mercupyridylmercuric chloride may be formed, by treatmentas indicated in the followingequation:

The actual laboratory procedure may be as follows:

Mercuric acetate grams) and pyridine (200 cc.) are heated together in aglass-lined autoclave for two hours at 180 C. After cooling, the product(175 cc.) is filtered from theinsoluble residue (33.5 grams) and placedin a vacuum distillation apparatus. From this, at least cc. of pyridinemay be removed and recovered. The residue in the flask, a dark tarrysubstance, is transferred to a beaker and covered with 100 cc. of ether.After slow stirring for some time the mass becomes granular. Thegranular mass, which is the crude acetate, is filtered and dried. Itmelts at 135 to C. The crude acetate is then extracted with hot benzenewith the aid of a small amount of norite. After filtering, the benzeneis allowed to cool, and white feathery needles of the purepyridylmercuric acetate separate out. This product is desirably againrecrystallized from benzene, and finally from carbon tetrachloride. Thepure acetate, in the form of white feathery needles, melts at about 178C. It is very soluble in both water and alcohol.

A portion of the pure pyridyimercuric acetate-- cred a rather stablelinkage, is rather easily broken by halogens, the halogens replacing themercury atom. Thus,40 grams of the above pure pyrldylmercuric chloridewas finely powdered and suspended in 80 cc. of water containing 50 gramsof potassium bromide. To this was added gradually 20 grams of brominewith stirring. After all of the bromine had been. added the mixture washeated gently on a waterbath for 15 minutes. After cooling, the mixturewas made alkaline with potassium hydroxide, and steam distilled. About7-5 cc, of distillate was collected; this was extracted with severalsmall portions of ether. The ether extracts were combined, and the etherevaporated, leaving an oil. This oil was distilled, and a portion (3grams) collected at 171-172 C. This, according to its boilin point, is3-bromopyridine. It was further confirmed as 3-bromopyridine by makingits picrate, which melted at 152-154 C. It also compared with a knownsample of B-bromopyridine.

The microorganism-devitalizing activity of the pyridylmercuric chlorideof the present invention is particularly well demonstrated in itsantiseptic activity with respect to various forms of bacteria. Forexample, tests in vitrio have shown the following activities:

Bacteriostatic index, or maximum The bacteriostatic index of the abovetable was determined in accordance with the method of Tetrault, which isas follows:

' To a sterile tube containing a known quantity of the pyridylmercuricchloride in aqueous solution, 9.5 cc. of a sterile agar solutioncontaining 2% agar, 1% peptone, and 0.3% beef extract is added. One 2mm. loopful of a twenty-four cul-' ture of the organism is then added tothe tube. The contents of the tube are then poured into a petri dish andincubated at 37 C. for forty-eight hours. The dish is then examined forgrowth of the organism. The experiment is repeated for differentdilutions of the substance until a dilution is reached beyond whichgrowth takes place. This dilution is expressed as cubic centimeters ofwater per gram of substance, and is the bacteriostatic index of theforegoing table.

The pyridylmercuric chloride of the present invention is likewise foundto be relatively nontoxic to mammals when used in bacteriostaticdosages.

The relatively increased solubility of the compound of the presentinvention in comparison, for example, with the analogous phenylmercuriccompound, in water is important, because it thereby becomes possible toprepare relatively stronger aqueous solutions which are exceedinglyefiective in devitalizing bacteria and microorganisms of other types.

Not only is the compound of the present invention useful as abacteriostatic or antiseptic agent, but it is also of demonstrableutility as a disinfectant, for seed disinfection, for example, and as afungicide, for preventing the moulding or decay of wood pulp, paper, andpaints, for example. In such uses, which are of an industrial character,the compound'of the present invention can be used directly in its crudecondition, without necessarily being purified.

In general, for its antiseptic use, the compound of the presentinvention is employed in its aqueous solutions, where it presents thecation RHg+. Antiseptic or bacteriostatic effects are or it may, withsatisfaction, be incorporated into ointments, with a greasy or unguentvehicle. In some circumstances, it may even be used in powdered solidform, for dusting on the infected location.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above compositions andmethods without departing from the scope of the invention, it isintended that all matter contained in the above description shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A microorganism devitalizing composition comprising pyridylmercuricchloride.

2. The method of devitalizing microorganisms which comprises subjectingthem to the action of Dyridylmercuric chloride.

RANDOLPH NORRIS SHREVE. MILLER WOODSON SWANEY.

